Valve Seat Soft Sealing Characteristics of Cryogenic Control Valve(Ⅱ): Sealing Characteristics at Liquid Nitrogen Temperature and Comprehensive Analysis

Polymer PTFE, PCTFE and PEEK were used as the soft sealing materials of cryogenic control valve and the relationship between leakage rateof valve seat and sealing pressure was analyzed at liquid nitrogen temperature (77 K). The tests of leakage rate in different inlet pressure and stability of inlet pressure were carried out. Based on those results, comparative analysis of soft sealing performance and application characteristics under the condition of room-low temperature and low-medium pressure were performed. Cryogenic valve with PTFE and PCTFE both have excellent valve seat sealing performance at the room temperature and low pressure, but at medium pressure, valve with PCTFE has more stable valve seat sealing performance. However, cryogenic valve with PEEK has the highest valve seat sealing performance and stability at low temperature.